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Here's why health experts say a booster dose of COVID vaccine is likely needed

Immunity is waning. Variants are emerging. So the booster, say health experts, is the next best thing.

TAMPA, Fla — With lots of talk recently about booster shots, you might be wondering why they’d be necessary. After all, MRNA technology is designed to teach our bodies to fight off COVID-19.

So, is it not working out the way medical experts thought it would?

“As our immune system, it gets a little sluggish, and so we see certain types of diseases actually need booster shots,” said Dr. Jill Roberts with USF Public Health.

Some vaccines last a lifetime. But it’s become clear that’s not the case for COVID vaccines.

Two of the most popular vaccines, Pfizer and Moderna, both use mRNA technology, which was supposed to give our body a blueprint to battle Covid-19. But now, months later, tests show that immunity is fading.

“Over time our body actually begins to ignore things that are foreign invaders,” Roberts said. “And so, if it does not see whatever it is looking for in a short amount of time, it basically goes to sleep.”

“And if you speak with Pfizer and Moderna they’ll tell you that they are trying to understand how the mechanics of the mRNA that they created, it’s like a program,” said Jay Wolfson with USF Health.

Wolfson drew an analogy to an app – still on your phone – but one that needs an update.

“So, you buy an app. And the app needs upgrading sometime,” he said.

Getting boosters isn’t new. For decades the annual flu shot, for example, has been successfully tweaked and adjusted to treat new strains of that virus.

But the booster – or app update - currently being recommended for COVID hasn’t been adjusted yet. It’s just more of the same.

So, why would that help protect against newer covid variants like delta?

“We have data from using the third booster shots to show that it really kicks up that immune response. And that it is protective against Delta virus,” Roberts said.

“But we honestly don’t know whether that third shot of the same stuff is going to last more than six or eight, nine or 12 months,” Wolfson said.

Unlike the flu shot, tweaks and changes in mRNA vaccines also require FDA approval. That takes up to a year.  

Meanwhile, immunity is waning. Variants are emerging. So the booster, say health experts, is the next best thing.

“We give you that original shot back again to wake your immune system back up again and say, remember this? Do what you did before,” Roberts said.

Health experts say a booster dose of Johnson & Johnson’s virus-based vaccine is also showing promise.

Medical experts say it’s likely that at some point in the future, manufacturers will combine flu and mRNA vaccines into a single shot that we’ll be able to receive annually with updated treatment for new strains or variants.

Drugmakers are already conducting tests on mRNA vaccines adjusted to battle covid variants and eventually, perhaps, a vaccine with longer-lasting effectiveness.

“So, I’m hopeful,” Roberts said. “I’m hopeful that one day we will see a much, much better shot for this.”

“All of the lab tests that were doing indicate that the third one is going to be the one that does it,” Wolfson said. “We hope it does.”

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